1. Field of the Invention
The present invention relates to a wind turbine, and more particularly, to a horizontal axis type wind turbine and a method of construction thereof.
2. Background Art
In general, the horizontal axis type wind turbine utilized for wind power generation, is installed on the top end of a tall tower so as to be able to acquire energy of natural wind efficiently.
For example, a wind turbine of this kind is disclosed in Japanese Patent Application Laid-open No. Toku-Kai-Sho 58-192977. As shown in FIG. 10, the wind turbine comprises a base member 101, a tower 102 mounted on the base member 101 and vertically extending, a nacelle 103 supported at the top of the tower 102 and a rotor 104 installed in the nacelle 103.
The tower 102 is hingedly connected with the base member 101 through a hinge 102a so as to swing between a standing position as illustrated in solid lines and a falling position as illustrated in two-dot chain lines. Further, a ginpole 106 is hingedly supported at the lower end thereof with the base member 101 and a tensile wire 107 is connected between the top end of the ginpole 106 and the upper portion of the tower 102. Further, the top end of the ginpole 106 is connected with a winch 109 through a towing wire 108.
Accordingly, when the winch 109 winds up the towing wire 108, the tower 102 can be raised from the falling position to the standing position through the ginpole 106 and the tensile wire 107. On the other hand, when the winch 109 winds down the towing wire 108, the tower 102 can be laid down from the standing position to the falling position.
This ginpole 106 and the tensile wire 107 are detachable so that they are installed when the maintenance is done and are removed when the maintenance is finished. When the wind turbine is operated with the ginpole 106 and tensile wire 107 removed, the lower end of the tower 102 is fixed to the base member 101 by bolts and the like so as to maintain the tower 102 in a standing position.
As another method of construction of the wind turbine, there is a method of using a mobile crane for raising the tower, mounting it on the base member, and attaching the nacelle and the rotor to the upper end of the tower.
According to the wind turbine disclosed in Toku-Kai-Sho 58-192977, since the tower 102 is hingedly connected at the lower end thereof with the base member 101 so as to swing between the standing and falling positions, maintenance and repair work to a generator or other equipment accommodated in the nacelle 103 can be done on the ground efficiently.
However, a large towing force is required in order to raise the tower 102 having a heavy nacelle at the top end thereof from the falling position to the standing position, therefore this swing type of the wind turbine is suitable for a wind turbine of small size.
On the other hand, according to the latter method of using a mobile crane, since the nacelle or the rotor are installed after the tower is built, it is possible to construct a relatively large size of the wind turbine by employing a large size mobile crane.
However, using the large size mobile crane and the like incurs an increase of procurement cost of construction equipment. Particularly, in case of construction works in islands, mountains, remote places and the like, the construction equipment procurement cost would increase. Furthermore, there would be a difficulty in securing a work space suitable for construction. Further, the maintenance cost would increase because of the necessity for a large size crane.
As a result, there are many cases where the construction of wind turbines must avoidably given up in spite of the fact that the power supply by wind turbines is most desired in these islands, mountains, remote places and the like and the case is similar with underdevelopment countries where the procurement of construction equipments like large size of cranes is generally difficult.
It is an object of the present invention to provide a method of constructing a relatively large size, horizontal axis type wind turbine capable of reducing construction cost without using a crane of large size.
In order to attain the object, the horizontal axis type wind turbine having a tower mounted on a base, a nacelle mounted on the tower and a rotor supported by the nacelle, the tower comprises a base tower member mounted on the base, a lower tower member hingedly connected at a lower end thereof with an upper end of the base tower member through a hinge so as to swing from a lying position to a standing position, a first stage connecting tower member connected at a lower end thereof with an upper end of the lower tower member and a highest stage connecting tower member connected at a lower end thereof with an upper end of a second highest stage connecting member. Further, the nacelle includes a tower penetrating hole through which the tower vertically penetrates and is formed by a plurality of nacelle sections divisible around the tower penetrating hole.